1. Field of the Invention
This invention relates to a broadband amplifier for the region of 1-10 GHz. The amplifier is fabricated from a pair of stagger-tuned, microwave, field-effect transistors (FET) incorporated in a microwave-integrated-circuit.
2. Description of the Invention
Microwave FETs which operate in the region of 1-10 GHz have been recently developed. These devices, when utilized in microwave-integrated-circuit (MIC) amplifiers, show promise for replacing some types of traveling wave tubes and other microwave-frequency devices. Up to this time, MIC amplifiers have used one or more cascaded microwave FETs in a microstrip medium with each microwave FET uniformly tuned to cover the same bandwidth. In order to obtain the uniformly tuned result, extremely sensitive tuning circuits are needed. A problem with this has been that a microstrip contains distributed circuit elements (i.e., characteristic impedance, inductance, and capacitance result from transmission line characteristics) for which only limited circuit values may be obtained. This severely restricts tuning and has led to complexity of the amplifier circuitry, thus affecting production capability in both performance and cost. In addition, the realizable gain-bandwidth product of a cascaded MIC amplifier using the uniformly tuned FET stages is not optimum due to these circuit value limitations.
What is needed is an MIC amplifier using cascaded FET stages which has a simple, realizable structure and will increase the bandwidth of the amplifier while maintaining maximum gain and a flat response.